Paper electrophoretic enrichment-assisted ultrasensitive SERS detection

To achieve sensitive detection of trace substances in fluids by surface-enhanced Raman spectroscopy (SERS), effective enrichment of molecules at subwavelength regions (hot spots) with a large enhancement is adopted. In this work, a glass fibre paper with Ag nanoparticles (AgNPs) is employed for electrodynamic enrichment of analytes in fluids by paper electrophoresis integrated with field amplification sample stacking (FASS) and capillary effects to obtain both Raman and SERS convenient and sensitive detection. With the help of electrophoretic enrichment on the glass fibre paper and surface plasmon enhancement on the AgNPs, this paper electrophoretic enrichment could improve the detection limit of Raman and SERS detection by more than an order of magnitude, even achieving a SERS detection limit of 10-17 M for Nile Blue A. Furthermore, this flexible SERS detection method can also detect trace organic contaminants at the ppt level in aquaculture and food applications.

Paper-Based Electrophoresis Microchip as a Powerful Tool for Bioanalytical Applications

This chapter describes the development of paper-based microchip electrophoresis (pME) devices for the separation of clinically relevant compounds. pME were fabricated by laser cut and thermal lamination process using polyester pouches. In addition, hand-drawn pencil electrodes were integrated to the device to perform capacitively coupled contactless conductivity detection (C⁴D). Finished device costs less than US$ 0.10 and did not require either sophisticated instrumentation or clean room facilities. Furthermore, pME is lightweight, easy to handle, flexible, and robust. pME-C⁴D device revealed an excellent capacity to separate BSA and creatinine in less than 150 s with baseline resolution. The device proposed in this chapter has proven to be a good alternative as a platform for the diagnosis of diseases from renal disorders such as diabetes mellitus and heart disease.